菊地  右馬

Kikuchi  Yuma
学科

一般科目

職名

准教授

学位

校務

専攻科幹事

クラブ顧問

卓球部


学歴
平成18年 3月 北海道大学理学部物理学科卒業
平成20年 3月 北海道大学大学院理学院宇宙理学専攻修士課程修了 修士(理学)
平成23年 3月 北海道大学大学院理学院宇宙理学専攻博士後期課程修了 博士(理学)(北海道大学)
職歴
平成23年 4月 大阪大学核物理研究センター特任研究員
平成26年 4月 理化学研究所仁科加速器研究センター基礎科学特別研究員
平成28年 4月 大阪市立大学理学研究科特任講師
平成30年 4月 徳山工業高等専門学校一般科目准教授(現在に至る)
賞罰
平成28年 3月 第10回日本物理学会若手奨励賞(理論核物理領域)
教育上の能力に関する事項
教育方法の実践例
大阪市立大学における学部学生に対する卒業研究指導 2016年度6月から3月

学部学生に対して量子力学から多体散乱までの内容をゼミで指導したほか、プログラミングや卒論作成の指導を行った。

大阪市立大学における修士学生に対する研究指導 2016年度4月から2月

修士学生に対して修論テーマの決定から数値計算や代数学などのゼミ、修論の執筆までを指導した。

作成した教科書・教材
該当なし
 
学校の評価
 
実務経験 特記事項
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その他
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職務上の能力に関する事項
資格・免許
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特許等
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実務経験 特記事項
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その他
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著作、学術論文等
学術論文
He8 and Li9 cluster structures in light nuclei (査読付) American Physical Society (APS) Physical Review C Physical Review C 102巻 2号 2469-9985 2020年 08月 27日

Naoyuki Itagaki, Tokuro Fukui, Junki Tanaka, Yuma Kikuchi

Large-amplitude quadrupole shape mixing probed by the (p, p ') reaction: A model analysis (査読付) OXFORD UNIV PRESS INC PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS 10号 2050-3911 2019年 10月

To discuss a possible observation of large-amplitude nuclear shape mixing by nuclear reaction, we employ a simple collective model and evaluate the transition densities with which the differential cross sections are obtained through the microscopic coupled-channel calculation. Assuming the spherical-to-prolate shape transition, we focus on large-amplitude shape mixing associated with the softness of the collective potential in the beta direction. We introduce a simple model based on the five-dimensional quadrupole collective Hamiltonian, which simulates a chain of isotopes that exhibit spherical-to-prolate shape phase transition. Taking Sm-154 as an example and controlling the model parameters, we study how the large-amplitude shape mixing affects the elastic and inelastic proton scatterings. The calculated results suggest that the inelastic cross section of the 2(2)(+) state shows us the important role of the quadrupole shape mixing. Koichi Sato, Takenori Furumoto, Yuma Kikuchi, Kazuyuki Ogata, Yukinori Sakuragi

Photodisintegration cross sections for resonant states and virtual states (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 99巻 3号 2469-9985 2019年 03月

The s-wave photodisintegration cross sections observed just above the neutron breakup threshold energy are calculated for resonant and virtual states by using a complex-scaled two-body model, which simulates the Be-9 nucleus with a Be-8 + n s-wave channel. We investigate the differences between behaviors of the resonance and virtual states in the photodisintegration cross sections near threshold energy in detail. It is shown that, in the present two-body model, resonant states very near the threshold energy produce a peak structure in the photodisintegration cross section that is similar that of the virtual state. Myagmarjav Odsuren, Yuma Kikuchi, Takayuki Myo, Hiroshi Masui, Kiyoshi Kato

Azimuthal angle distributions of neutrons emitted from the Be-9(gamma, n) reaction with linearly polarized gamma rays (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 98巻 6号 2469-9985 2018年 12月

The electromagnetic transitions of Be-9 with linearly polarized gamma rays are calculated by using the alpha + alpha + n three-body model and the complex-scaled solutions of the Lippmann-Schwinger equation; the azimuthal angle distributions of the emitted neutrons are investigated. We calculate the anisotropy parameter as a function of the photon incident energy E-gamma and discuss how sensitive the anisotropy parameter is to nuclear structure and transition modes. The result suggests that the azimuthal angle distribution of neutrons emitted from the Be-9(gamma, n) reaction with the linearly polarized gamma rays is useful to identify the resonances in the final states even if it is not clearly observed in the cross section. Yuma Kikuchi, Kazuyuki Ogata, Takehito Hayakawa, Satoshi Chiba

Virtual States in the Complex Scaling Method (査読付) AMER INST PHYSICS PROCEEDINGS OF THE 4TH INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR CLUSTER PHYSICS (SOTANCP4) PROCEEDINGS OF THE 4TH INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR C 2018年

A virtual state plays an important role in reaction cross sections just above the breakup threshold energy, such as producing the peak behaviour. However, the virtual state cannot be directly obtained as an isolated pole solution in the complex scaling method (CSM) because of a limit of the scaling angle in the CSM. Recently, we proposed a useful approach to find the pole position of the virtual state using the continuum level density (CLD), the scattering phase shift, and scattering length calculated in the CSM [4]. On the basis of the proposed method, we investigate the photo-disintegration cross sections of resonance and virtual states above the threshold energy to see their differences. Kiyoshi Kato, Myagmarjav Odsuren, Takayuki Myo, Hiroshi Masui, Yuma Kikuchi

A Virtual State in a Two-Body System Using the Complex Scaling Method (査読付) Institute of Physics Publishing Journal of Physics: Conference Series Journal of Physics: Conference Series 863巻 1号 pp.012038~ 1742-6596 2017年 07月 04日

In association with the property of the 1/2+ state observed just above the 8Be(0+)+n threshold energy in 9Be, we investigate the photo-disintegration cross section of an s-state in a schematic two-body system using the complex scaling method. M. Odsuren, Y. Kikuchi, T. Myo, M. Aikawa, G. Khuukhenkhuu, K. Kato

Photodisintegration cross section of<sup>9</sup>Be up to E<inf>γ</inf> = 16 MeV in the α + α + n three-body model Journal of Physics: Conference Series Journal of Physics: Conference Series 863巻 1号 1742-6596 2017年 07月 04日

? Published under licence by IOP Publishing Ltd. We investigate the photodisintegration cross section (PDXS) of9Be in low and higher energy regions by using the α + α + n three-body model and the complex scaling method (CSM). The calculated photodisinegration cross section of well reproduces the recent experimental data, and shows that the transitions into the8Be(2+) + n states dominate the cross section in the energy region of 6 ?Eγ ? 16 MeV. Y. Kikuchi, M. Odsuren, T. Myo, T. Myo, K. Kato

Virtual-state character of the two-body system in the complex scaling method (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 95巻 6号 2469-9985 2017年 06月

In association with the property of the 1/2(+) state observed just above the Be-8(0(+)) + n threshold energy in Be-9, we investigate the photodisintegration cross section of an s state in a simple schematic two-body model using the complex scaling method. The photodisintegration cross section, continuum level density, scattering phase shifts, and scattering length are discussed in relation with the virtual state. These scattering observables show strong divergences when a virtual state is located near the physical scattering region. Myagmarjav Odsuren, Yuma Kikuchi, Takayuki Myo, Gonchigdorj Khuukhenkhuu, Hiroshi Masui, Kiyoshi Kato

The first unbound states of mirror Be-9 and B-9 nuclei (査読付) E D P SCIENCES ND 2016: INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY ND 2016: INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY 146巻 2100-014X 2017年

The structures of the first excited states of mirror Be-9 and B-9 nuclei are studied by using the alpha + alpha + N three-body model and the complex scaling method. The resonance energy with a decay width of the 1/2(+) state of B-9 is calculated by taking into account the consistency with photodisintegration cross sections of Be-9 into the 1/2(+) state. We also compare the results with the measured data and other theories. Myagmarjav Odsuren, Yuma Kikuchi, Takayuki Myo, Masayuki Aikawa, Kiyoshi Kato

Determination of a dineutron correlation in Borromean nuclei via a quasi- free knockout (p, pn) reaction (査読付) OXFORD UNIV PRESS INC PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS 10号 2050-3911 2016年 10月

To discuss the dineutron correlation in the ground state, the quasi-free neutron knockout reaction on He-6 is investigated. In the present work, the momentum distribution of the two emitted neutrons is calculated with the alpha + n + n three-body model and a simple reaction model to assess the effects of the knockout process via the He-5 resonance and the target dependence in the momentum distribution. A clear signature of the dineutron correlation can be obtained by choosing the kinematical condition so the process via the He-5 resonance is excluded because the He-5 resonance drastically changes the momentum distribution. Using the proton target is important in the quantitative discussion on the dineutron correlation by the knockout reaction. In addition to theoretical arguments, a possible experimental setup to determine the dineutron correlation via the quasi-free knockout reaction is considered. Yuma Kikuchi, Kazuyuki Ogata, Yuki Kubota, Masaki Sasano, Tomohiro Uesaka

Photodisintegration cross section of Be-9 up to 16 MeV in the alpha plus alpha plus n three-body model (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 93巻 5号 2469-9985 2016年 05月

The photodisintegration of Be-9 in the energy region lower than E-gamma = 16 MeV is investigated by using the alpha + alpha + n three-body model and the complex scaling method. The cross section exhibits two aspects in two different energy regions. In the low-energy region up to E-gamma = 6 MeV, the cross section is explained by the transition strengths into the excited resonant states of Be-9, while the dipole transition into the nonresonant continuum states of Be-8(2(+)) + n dominates the cross section in the energy region of 6 <= E-gamma <= 16 MeV. Furthermore, it is shown that the dipole strength at E-gamma similar to 8 MeV is understood to be caused by the single-neutron excitation from the Be-8(2(+)) circle times nu p(3/2) configuration in the ground state. Yuma Kikuchi, Myagmarjav Odsuren, Takayuki Myo, Kiyoshi Kato

Photodisintegration Cross Section of the 9Be(1/2+) State in the Complex Scaling Method (査読付) Proceedings of the 2014 Symposium on Nuclear Data Proceedings of the 2014 Symposium on Nuclear Data pp.99~104 2016年 03月

Myagmarjav Odsuren, Yuma Kikuchi, Takayuki Myo, Masayuki Aikawa, Kiyoshi Kato

Microscopic effective reaction theory for direct nuclear reactions (査読付) E D P SCIENCES CNR*15 - 5TH INTERNATIONAL WORKSHOP ON COMPOUND-NUCLEAR REACTIONS AND RELATED TOPICS CNR*15 - 5TH INTERNATIONAL WORKSHOP ON COMPOUND-NUCLEAR REACTIONS AND RELATED TOPICS 122巻 2100-014X 2016年

Some recent activities with the microscopic effective reaction theory (MERT) on elastic, inelastic, breakup, transfer, and knockout processes are reviewed briefly. As a possible alternative to MERT, a description of elastic and inelastic scattering with the continuum particle-vibration coupling (cPVC) method is also discussed. Kazuyuki Ogata, Kosho Minomo, Masakazu Toyokawa, Michio Kohno, Takuma Matsumoto, Masanobu Yahiro, Yuma Kikuchi, Tokuro Fukui, Kazuki Yoshida, Kazuhito Mizuyama

Photodisintegration of Be-9 and the importance of the unbound 1/2(+) state (査読付) E D P SCIENCES 13TH INTERNATIONAL SYMPOSIUM ON ORIGIN OF MATTER AND EVOLUTION OF GALAXIES (OMEG2015) 13TH INTERNATIONAL SYMPOSIUM ON ORIGIN OF MATTER AND EVOLUTION OF GALAXIES (OMEG2015) 109巻 2100-014 2016年

The photodisintegration cross section of the Be-9(1/2(+)) state is investigated in a framework of the alpha + alpha + n three-body model. The 1/2(+) state of Be-9 locates just above the three-body threshold, and the s-wave neutron property of this state is a long-standing problem. It has been a topic of quite interest in relation to the breakup mechanism of Be-9 into the Be-8(0(+)) + n and (alpha + alpha + n) channels. Myagmarjav Odsuren, Yuma Kikuchi, Takayuki Myo, Masayuki Aikawa, Kiyoshi Kato

Virtual-state character of the Be 9 1 / 2 + state in the Be 9 (γ, n) Be 8 reaction (査読付) American Physical Society Physical Review C - Nuclear Physics Physical Review C - Nuclear Physics 92巻 1号 1089-490X 2015年 07月 27日

We study the character of the first excited 1 / 2 + state of Be 9, which is observed as a low-lying sharp peak in the cross section of Be 9 (γ, n) 2 He 4 just above the Be 8 + n threshold. Using the α + α + n three-body model, we describe the ground and excited unbound states of Be 9 above the α + α + n threshold. Applying the complex scaling method to the three-body model, we find no 1 / 2 + resonant solutions with the scaling angle of θ ? 15, while the low-lying peak in the photodisintegration cross section is reproduced in the present calculation. It is found that the Be 8 + n continuum states dominate the low-lying peak in the cross section. Furthermore, using the analytical continuation of the coupling constant of the three-body interaction for the α + α + n system, we discuss the virtual-state character of the 1 / 2 + state. Myagmarjav Odsuren, Yuma Kikuchi, Takayuki Myo, Masayuki Aikawa, Kiyoshi Kato

Virtual-state character of the Be-9 1/2(+) state in the Be-9(gamma,n)Be-8 reaction (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 92巻 1号 2469-9985 2015年 07月

We study the character of the first excited 1/2(+) state of Be-9, which is observed as a low-lying sharp peak in the cross section of Be-9(gamma,n)2(4)He just above the Be-8 + n threshold. Using the alpha + alpha + n three-body model, we describe the ground and excited unbound states of Be-9 above the alpha + alpha + n threshold. Applying the complex scaling method to the three-body model, we find no 1/2(+) resonant solutions with the scaling angle of theta <= 15 degrees, while the low-lying peak in the photodisintegration cross section is reproduced in the present calculation. It is found that the Be-8 + n continuum states dominate the low-lying peak in the cross section. Furthermore, using the analytical continuation of the coupling constant of the three-body interaction for the alpha + alpha + n system, we discuss the virtual-state character of the 1/2(+) state. Myagmarjav Odsuren, Yuma Kikuchi, Takayuki Myo, Masayuki Aikawa, Kiyoshi Kato

Recent development of complex scaling method for many-body resonances and continua in light nuclei (査読付) ELSEVIER PROGRESS IN PARTICLE AND NUCLEAR PHYSICS PROGRESS IN PARTICLE AND NUCLEAR PHYSICS 79巻 pp.1~56 0146-6410 2014年 11月

The complex scaling method (CSM) is a useful similarity transformation of the Schrodinger equation, in which bound-state spectra are not changed but continuum spectra are separated into resonant and non-resonant continuum ones. Because the asymptotic wave functions of the separated resonant states are regularized by the CSM, many-body resonances can be obtained by solving an eigenvalue problem with the L-2 basis functions. Applying this method to a system consisting of a core and valence nucleons, we investigate many-body resonant states in weakly bound nuclei very far from the stability lines. Non-resonant continuum states are also obtained with the discretized eigenvalues on the rotated branch cuts. Using these complex eigenvalues and eigenstates in CSM, we construct the extended completeness relations and Green's functions to calculate strength functions and breakup cross sections. Various kinds of theoretical calculations and comparisons with experimental data are presented. (C) 2014 Elsevier B.V. All rights reserved. Takayuki Myo, Yuma Kikuchi, Hiroshi Mosui, Kiyoshi Kato

A resonance problem on the low-lying resonant state in the Be-9 system (査読付) IOP PUBLISHING LTD 3RD INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR CLUSTER PHYSICS 3RD INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR CLUSTER PHYSICS 569巻 1742-6588 2014年

The photo-disintegration cross section of Be-9 is investigated in a framework of the alpha + alpha + n three-body cluster model. Much interest is concentrated on the nature of the 1/2(+) state of Be-9 located just above the three-body threshold. The existence of this 1/2(+) resonance is a long-standing problem and has been a topic of quite interest in relation to the breakup mechanism of Be-9 into the Be-8(0(+))+n and (alpha + alpha +n) channels. The newly measured breakup cross sections of the 1/2(+) state of Ref. [1] is inconsistent with the old experimental values [2, 3]. The purpose of this study is to clarify the properties of the 1/2(+) state of Be-9 with the possibility of a genuine three-body (alpha + alpha + n) resonance or the two-body (Be-8(0(+))+n) virtual state. Myagmarjav Odsuren, Kiyoshi Kato, Yuma Kikuchi, Masayuki Aikawa, Takayuki Myo

Mechanism of Coulomb breakup reactions of two-neutron halo nuclei He-6 and Li-11 (査読付) IOP PUBLISHING LTD 3RD INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR CLUSTER PHYSICS 3RD INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR CLUSTER PHYSICS 569巻 1742-6588 2014年

We investigate the three-body Coulomb breakup reactions of two-neutron halo nuclei and discuss the correlations of every binary subsystem such as of core-n and n-n by showing the invariant mass spectra. It is found that the final-state interactions of core-n and n-n binary subsystems dominantly determine the observed energy distributions of the breakup cross sections, such as the low-lying enhancements. Furthermore, we investigate the effects of the Li-9 core excitations on the Coulomb breakup cross section of Li-11. It is shown that the integrated E1 strength at low energy region is reduced by similar to 15 % by the inclusion of the Li-9 core excitations. Yuma Kikuchi, Takayuki Myo, Kiyoshi Kato, Kiyomi Ikeda

Two neutron decay from the 21+ state of 6He (査読付) American Physical Society Physical Review C - Nuclear Physics Physical Review C - Nuclear Physics 88巻 2号 1089-490X 2013年 08月 30日

Decay mode of the 21+ resonant state of 6He populated by the 6He breakup reaction by 12C at 240 MeV/nucleon is investigated. The continuum-discretized coupled-channels method is adopted to describe the formation of the 21+ state, whereas its decay is described by the complex-scaled solutions of the Lippmann-Schwinger equation. From analysis of invariant mass spectra with respect to the α-n and n-n subsystems, coexistence of two decay modes is found. One is the simultaneous decay of two neutrons correlating with each other and the other is the emission of two neutrons to the opposite directions. The latter is found to be free from the final-state interaction and suggests existence of a dineutron in the 21+ state of 6He. ? 2013 American Physical Society. Yuma Kikuchi, Takuma Matsumoto, Kosho Minomo, Kazuyuki Ogata

Study of the Isospin Mixing in 6Li with α + p + n Three-Body Model (査読付) Few-Body Systems Few-Body Systems 54巻 7-10号 pp.1381~1384 0177-7963 2013年 08月

We calculate the isospin mixing probabilities for both T = 0 and T = 1 states of 6Li systematically, and compare them to clarify the relation between the structure of 6Li and the isospin mixing probabilities. As a result, the effect of halo structure on the isospin mixing cannot be seen clearly. The effect of the coupling to the continuum states such as of 5He + p and 5Li + n is suggested. ? 2013 Springer-Verlag Wien. N. Kurihara, Y. Kikuchi, K. Kato

Two neutron decay from the 2(1)(+) state of He-6 (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 88巻 2号 2469-9985 2013年 08月

Decay mode of the 2(1)(+) resonant state of He-6 populated by the He-6 breakup reaction by C-12 at 240 MeV/nucleon is investigated. The continuum-discretized coupled-channels method is adopted to describe the formation of the 2(1)(+) state, whereas its decay is described by the complex-scaled solutions of the Lippmann-Schwinger equation. From analysis of invariant mass spectra with respect to the alpha-n and n-n subsystems, coexistence of two decay modes is found. One is the simultaneous decay of two neutrons correlating with each other and the other is the emission of two neutrons to the opposite directions. The latter is found to be free from the final-state interaction and suggests existence of a dineutron in the 2(1)(+) state of He-6. Yuma Kikuchi, Takuma Matsumoto, Kosho Minomo, Kazuyuki Ogata

Five-body resonances of C-8 using the complex scaling method (vol 85, 034338, 2012) (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 87巻 4号 0556-2813 2013年 04月

Takayuki Myo, Yuma Kikuchi, Kiyoshi Kato

Coulomb breakup reactions of 11Li in the coupled-channel 9Li+n+n model (査読付) American Physical Society Physical Review C - Nuclear Physics Physical Review C - Nuclear Physics 87巻 3号 1089-490X 2013年 03月 05日

We investigate the three-body Coulomb breakup of a two-neutron halo nucleus 11Li. We use the coupled-channel 9Li+n+n three-body model, which includes the coupling between last neutron states and the various two-particle-two-hole (2p-2h) configurations in 9Li due to the tensor and pairing correlations. The three-body scattering states of 11Li are described by using the combined methods of complex scaling and the Lippmann-Schwinger equation. The calculated breakup cross section successfully reproduces the experiments. The large mixing of the s state in the halo ground state of 11Li is shown to play an important role in the explanation of shape and strength of the breakup cross section. In addition, we predict the invariant mass spectra for binary subsystems of 11Li. It is found that the two kinds of virtual s states of 9Li-n and n-n systems in the final three-body states of 11Li largely contribute to make low-lying peaks in the invariant mass spectra. On the other hand, in the present analysis, it is suggested that the contributions of the p-wave resonances of 10Li are hardly confirmed in the spectra. ? 2013 American Physical Society. Yuma Kikuchi, Takayuki Myo, Kiyoshi Kato, Kiyomi Ikeda

Coulomb breakup reactions of Li-11 in the coupled-channel Li-9 + n plus n model (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 87巻 3号 2469-9985 2013年 03月

We investigate the three-body Coulomb breakup of a two-neutron halo nucleus Li-11. We use the coupled-channel Li-9 + n + n three-body model, which includes the coupling between last neutron states and the various two-particle-two-hole (2p-2h) configurations in Li-9 due to the tensor and pairing correlations. The three-body scattering states of Li-11 are described by using the combined methods of complex scaling and the Lippmann-Schwinger equation. The calculated breakup cross section successfully reproduces the experiments. The large mixing of the s state in the halo ground state of Li-11 is shown to play an important role in the explanation of shape and strength of the breakup cross section. In addition, we predict the invariant mass spectra for binary subsystems of Li-11. It is found that the two kinds of virtual s states of Li-9-n and n-n systems in the final three-body states of Li-11 largely contribute to make low-lying peaks in the invariant mass spectra. On the other hand, in the present analysis, it is suggested that the contributions of the p-wave resonances of Li-10 are hardly confirmed in the spectra. DOI: 10.1103/PhysRevC.87.034606 Yuma Kikuchi, Takayuki Myo, Kiyoshi Kato, Kiyomi Ikeda

Five-body resonances of C-8 using the complex scaling method (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 85巻 3号 2469-9985 2012年 03月

We study the resonance spectroscopy of the proton-rich nucleus C-8 in the alpha + p + p + p + p cluster model. Many-body resonances are treated on the correct boundary condition as the Gamow states using the complex scaling method. We obtain the ground state of 8C as a five-body resonance for the first time, which has dominantly the subclosed (p(3/2))(4) configuration and agrees with the recent experiment for energy and decay width. We predict the second 0(+) state with the excitation energy of 5.6 MeV, which corresponds to the 2p2h state from the ground state. We evaluate the occupation numbers of four valence-protons in the C-8 states and also the J(pi) distribution of proton-pair numbers of the two 0(+) states of C-8. The ground state involves a large amount of the 2(+) proton-pair fraction, while the excited 0(2)(+) state almost consists of two of the 0(+) proton pairs, which can be understood from the (p(3/2))(2)(p(1/2))(2) configuration. We also discuss the mirror symmetry between C-8 and He-8 with an alpha+four nucleon picture. It is found that the 0(+) states retain the mirror symmetry well for the configuration properties of two nuclei. Takayuki Myo, Yuma Kikuchi, Kiyoshi Kato

Binary Subsystem Correlations in Coulomb Breakup Reactions of Two-Neutron Halo Nuclei (査読付) PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT 196号 pp.283~288 0375-9687 2012年

We investigate the three-body Coulomb breakup reactions of two-neutron halo nuclei and discuss the effect of binary subsystem correlations such as of core-n and n-n. We furthermore calculate the invariant mass spectra. It is found that the final-state interactions of core-n and n-n binary subsystems dominantly determine the observed structures of the breakup cross sections, such as the low-lying enhancements. Yuma Kikuchi

Four-body resonances of 7B using the complex scaling method (査読付) American Physical Society Physical Review C - Nuclear Physics Physical Review C - Nuclear Physics 84巻 6号 1089-490X 2011年 12月 06日

We study the resonance spectroscopy of the proton-rich nucleus 7B in the 4He+p+p+p cluster model. Many-body resonances are treated under the correct boundary condition as Gamow states using the complex scaling method. We predict five resonances of 7B and evaluate the spectroscopic factors of the 6Be-p components. The importance of the 6Be(2+)-p component is shown in several states of 7B this is a common feature of 7He, a mirror nucleus of 7B. For only the ground state of 7B, the mixing of the 6Be(2+) state is larger than that of 6He(2+) in 7He, which indicates a breaking of mirror symmetry. This is caused by the small energy difference between 7B and the excited 6Be(2+) state, the origin of which is Coulomb repulsion. ? 2011 American Physical Society. Takayuki Myo, Yuma Kikuchi, Kiyoshi Kato

Four-body resonances of B-7 using the complex scaling method (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 84巻 6号 2469-9985 2011年 12月

We study the resonance spectroscopy of the proton-rich nucleus B-7 in the He-4 + p + p + p cluster model. Many-body resonances are treated under the correct boundary condition as Gamow states using the complex scaling method. We predict five resonances of B-7 and evaluate the spectroscopic factors of the Be-6-p components. The importance of the Be-6(2(+))-p component is shown in several states of B-7; this is a common feature of He-7, a mirror nucleus of B-7. For only the ground state of B-7, the mixing of the Be-6(2(+)) state is larger than that of He-6(2(+)) in He-7, which indicates a breaking of mirror symmetry. This is caused by the small energy difference between B-7 and the excited Be-6(2(+)) state, the origin of which is Coulomb repulsion. Takayuki Myo, Yuma Kikuchi, Kiyoshi Kato

Three-body model analysis of alpha plus d elastic scattering and the H-2(alpha,gamma)Li-6 reaction in complex-scaled solutions of the Lippmann-Schwinger equation (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 84巻 6号 0556-2813 2011年 12月

We investigate the alpha + d elastic scattering and the radiative capture reaction of H-2(alpha,gamma)Li-6 based on the alpha + p + n three-body model. The alpha + d scattering states are described by using the complex-scaled solutions of the Lippmann-Schwinger equation. We calculate the elastic phase shifts for the alpha + d scattering and the radiative capture cross section of Li-6. We evaluate the contributions of the alpha + p + n structures in those observables. It is found that in the alpha + d scattering process, the deuteron breakup and the rearrangement to the He-5 + p and Li-5 + n channels play prominent roles in reproducing the observed phase shifts and radiative capture cross section. Yuma Kikuchi, Nozomi Kurihara, Atsushi Wano, Kiyoshi Kato, Takayuki Myo, Masaaki Takashina

TWO-NEUTRON CORRELATIONS IN HALO NUCLEI VIA COULOMB BREAKUP REACTIONS (査読付) WORLD SCIENTIFIC PUBL CO PTE LTD INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS 20巻 4号 pp.843~846 0218-3013 2011年 04月

We investigate the three-body Coulomb breakup of a two-neutron halo nucleus, He-6. We calculate the breakup cross section and the invariant mass spectra by using the complex-scaled solutions of the Lippmann-Schwinger equation, and discuss the relations between the structures in these observables and the n-n and alpha-n correlations in He-6. Yuma Kikuchi, Kiyoshi Kato, Takayuki Myo, Masaaki Takashina, Kiyomi Ikeda

DI-NEUTRON CORRELATION IN He-6 THROUGH COULOMB BREAKUP REACTIONS (査読付) WORLD SCIENTIFIC PUBL CO PTE LTD MODERN PHYSICS LETTERS A MODERN PHYSICS LETTERS A 25巻 21-23号 pp.1907~1910 0217-7323 2010年 07月

We investigate the three-body Coulomb breakup of a two-neutron halo nucleus, He-6. The three-body scattering states of He-6 are described by using the Complex-scaled solutions of the Lippmann-Schwinger equation. We calculate the breakup cross section and the invariant mass spectra, and discuss the relations between the structures in these observables and the n-n and alpha-n correlations of He-6. Yuma Kikuchi, Kiyoshi Kato, Takayuki Myo, Masaaki Takashina, Kiyomi Ikeda

Two-neutron correlations in He6 in a Coulomb breakup reaction (査読付) American Physical Society Physical Review C - Nuclear Physics Physical Review C - Nuclear Physics 81巻 4号 1089-490X 2010年 04月 16日

We investigate the three-body Coulomb breakup of a two-neutron halo nucleus, He6. Based on the α+n+n model, the three-body scattering states of He6 are described by using the combined methods of the complex scaling and the Lippmann-Schwinger equation. We calculate the breakup cross section, the two-dimensional energy distributions, and the invariant mass spectra for the E1 transition of He6. We discuss the relations between the structures in these strengths and the n-n and α-n correlations of He6. It is found that the He5 resonance in the final states contributes to make a low-energy enhancement of the strength. The n-n final-state interaction also contributes to enhance the strength globally. However, the ground-state correlations of He6, such as a dineutron, are difficult to recognize in the strength because of the dominant effect of the final-state interaction. ? 2010 The American Physical Society. Yuma Kikuchi, Kiyoshi Kato, Takayuki Myo, Masaaki Takashina, Kiyomi Ikeda

Two-neutron correlations in He-6 in a Coulomb breakup reaction (査読付) AMER PHYSICAL SOC PHYSICAL REVIEW C PHYSICAL REVIEW C 81巻 4号 2469-9985 2010年 04月

We investigate the three-body Coulomb breakup of a two-neutron halo nucleus, He-6. Based on the alpha + n + n model, the three-body scattering states of He-6 are described by using the combined methods of the complex scaling and the Lippmann-Schwinger equation. We calculate the breakup cross section, the two-dimensional energy distributions, and the invariant mass spectra for the E1 transition of He-6. We discuss the relations between the structures in these strengths and the n-n and alpha-n correlations of He-6. It is found that the He-5 resonance in the final states contributes to make a low-energy enhancement of the strength. The n-n final-state interaction also contributes to enhance the strength globally. However, the ground-state correlations of He-6, such as a dineutron, are difficult to recognize in the strength because of the dominant effect of the final-state interaction. Yuma Kikuchi, Kiyoshi Kato, Takayuki Myo, Masaaki Takashina, Kiyomi Ikeda

Coulomb Breakup Reactions in Complex-Scaled Solutions of the Lippmann-Schwinger Equation (査読付) PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE PROGRESS OF THEORETICAL PHYSICS PROGRESS OF THEORETICAL PHYSICS 122巻 2号 pp.499~510 0033-068X 2009年 08月

We propose a new method to describe three-body breakups of nuclei, in which the Lippmann-Schwinger equation is solved in combination with the complex scaling method. The complex-scaled solutions of the Lippmann-Schwinger equation (CSLS) enable us to treat boundary conditions of many-body open channels correctly and to describe a many-body breakup amplitude from the ground state. The Coulomb breakup cross section from the He-6 ground state into He-4+n+n three-body decaying states as a function of the total excitation energy is calculated using CSLS, and the result well reproduces the experimental data. Furthermore, the two-dimensional energy distribution of the El transition strength is obtained and the importance of the He-5(3/2(-)) resonance is confirmed. It is shown that CSLS is a promising method to investigate correlations of subsystems in three-body breakup reactions of weakly bound nuclei. Yuma Kikuchi, Takayuki Myo, Masaaki Takashina, Kiyoshi Kato, Kiyomi Ikeda

TENSOR CORRELATION IN He AND Li ISOTOPES BASED ON TENSOR OPTIMIZED SHELL MODEL WITH UNITARY CORRELATION OPERATOR (査読付) WORLD SCIENTIFIC PUBL CO PTE LTD INTERNATIONAL JOURNAL OF MODERN PHYSICS A INTERNATIONAL JOURNAL OF MODERN PHYSICS A 24巻 11号 pp.2150~2158 0217-751X 2009年 04月

We show the importance of the tensor correlation on the structures of He and Li isotopes. We develop the tensor optimized shell model (TOSM) to describe the strong tensor correlation of the nuclear force in nuclei. We investigate the exotic structures of (9,10,11)Li based on the (9)Li+n+n model where TOSM is used for (9)Li. The coupling between the tensor correlation in (9)Li and the extra two neutrons emerges Pauli-blocking, which increases the s(2) component and develops the halo structure in (11)Li.We further treat the short range repulsion of the nuclear force by the unitary correlation operator method (UCOM), while the tensor correlation is described by TOSM. We propose a new approach of TOSM+UCOM to describe nuclei from the nuclear force. Takayuki Myo, Kiyoshi Kato, Yuma Kikuchi, Hiroshi Toki, Kiyomi Ikeda

ANALYSIS ON TWO-NEUTRON CORRELATION THROUGH DALITZ PLOT OF COULOMB BREAKUP REACTION FOR He-6 (査読付) WORLD SCIENTIFIC PUBL CO PTE LTD INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS 17巻 10号 pp.2368~2373 0218-3013 2008年 11月

A new method to describe the three-body decaying states is developed. In this method, the Lippmann-Schwinger equation is combined with the complex scaling method to take the correct boundary condition into account. For the application, the E1 transition strength of He-6 is investigated. The energy and Dalitz distributions of the E1 transition are calculated, and the internal correlation of He-6 is discussed. As results, it is found that the He-6 -> He-5(3/2(-)) + n -> He-4+n+n sequential decay process is dominant in the E1 transition reaction of He-6. Yuma Kikuchi, Kiyoshi Kato, Takayuki Myo, Masaaki Takashina, Kiyomi Ikeda

A SYSTEMATIC STUDY OF THE TENSOR CORRELATION IN He AND Li ISOTOPES (査読付) WORLD SCIENTIFIC PUBL CO PTE LTD MODERN PHYSICS LETTERS A MODERN PHYSICS LETTERS A 23巻 27-30号 pp.2577~2580 0217-7323 2008年 09月

We investigate the tensor correlations in He and Li isotopes systematically. We propose the tensor-optimized shell model (TOSM) to describe the strong tensor correlation arising from the bare nuclear force in nuclei. Using TOSM for Li isotopes, we investigate the anomalous structures of Li-9,Li-10,Li-11 based on the Li-9+n+n model where the Li-9 cluster is described by TOSM. As a result, the couplings between the tensor correlation in Li-9 and the extra two neutrons emerge Pauli-blocking, which naturally increases the s(2) component to develop the halo structure in Li-11. We further describe the short-range correlation arising from the repulsive core in the bare nuclear force by the unitary correlation operator method (UCOM). We propose the new framework of TOSM+UCOM for the nuclear structure study starting from the bare nuclear force. Takayuki Myo, Hiroshi Toki, Satoru Sugimoto, Kiyoshi Kato, Yuma Kikuchi, Kiyomi Ikeda

Systematic study of (9,10,11)Li with the tensor and pairing correlations (査読付) PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE PROGRESS OF THEORETICAL PHYSICS PROGRESS OF THEORETICAL PHYSICS 119巻 4号 pp.561~581 0033-068X 2008年 04月

We make a systematic study of Li isotopes (A = 9, 10, 11) in the tensor optimized shell model for (9)Li and treat the additional valence neutrons in the cluster model approach by taking into account the Pauli-blocking effect caused by the tensor and pairing correlations. We describe the tensor correlations in (9)Li fully in the tensor-optimized shell model, where the variation of the size parameters of the single particle orbits is essential for getting strong tensor correlations. We have shown in our previous study that in (10,11)Li the tensor and pairing correlations in (9)Li are Pauli-blocked by additional valence neutrons, which make the p-shell configurations pushed up in energy. As a result, the s(2) valence neutron component increases to reveal the halo structure of (11)Li and the inversion phenomenon of the single particle spectrum in (10)Li arises. Following the previous study, we demonstrate the reliability of our framework by performing a detailed systematic analysis of the structures of (9,10,11)Li, such as the charge radius, the spatial correlation of halo neutrons of (11)Li and the electromagnetic properties of Li isotopes. The detailed effects of the Pauli-blocking on the spectroscopic properties of (10,11)Li are also discussed. It is found that the blocking acts strongly for the (11)Li ground state rather than for (10)Li and for the dipole excited states of (11)Li, which is mainly caused by the interplay between the tensor correlation in (9)Li and the halo neutrons. The results obtained in these analyses clearly show that the inert core assumption of (9)Li is not realistic to explain the anomalous structures observed in (10,11)Li. For the dipole excitation spectrum of (11)Li, the effect of the final state interactions is discussed in terms of the dipole strength function. Takayuki Myo, Yuma Kikuchi, Kiyoshi Kato, Hiroshi Toki, Kiyomi Ikeda

その他
<sup>6</sup>Heのクーロン分解における2中性子相関 原子核研究 原子核研究 60巻 2号 pp.37‐47~ 0367-4169 2016年 03月

菊地右馬

Many-body resonances and continuum states above many-body decay thresholds IOP PUBLISHING LTD 3RD INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR CLUSTER PHYSICS 3RD INTERNATIONAL WORKSHOP ON STATE OF THE ART IN NUCLEAR CLUSTER PHYSICS 569巻 1742-6588 2014年

We study the resonance spectroscopy of the He isotopes and their mirror, proton-rich nuclei with an alpha + N + N + N + N cluster model. Many-body resonances are treated with the correct boundary condition as the Gamow states using the complex scaling method. We obtain the resonances up to the five-body decaying states in He-8 and C-8. The spectrum agrees with the recent experiment systematically for energies and decay widths and we predict several resonances. We also discuss the mirror symmetry breaking of He isotopes and their mirror nuclei for the configurations and the spatial distributions of the valence nucleons. K. Kato, T. Myo, Y. Kikuchi

Coulomb Breakup Reactions of Two-Neutron Halo Nuclei He-6 and Li-11 Using Complex-Scaled Solutions of the Lippmann-Schwinger Equation SPRINGER WIEN FEW-BODY SYSTEMS FEW-BODY SYSTEMS 54巻 7-10号 pp.1445~1448 0177-7963 2013年 08月

We investigate the three-body Coulomb breakup reactions of two-neutron halo nuclei and discuss the effect of binary subsystem correlations such as of core-n and n-n. We furthermore calculate the invariant mass spectra. It is found that the final-state interactions of core-n and n-n binary subsystems dominantly determine the observed structures of the breakup cross sections, such as the low-lying enhancements. Y. Kikuchi, T. Myo, K. Kato, K. Ikeda

Mechanisms of Coulomb breakup reactions of He-6 and Li-11 IOP PUBLISHING LTD 10TH INTERNATIONAL CONFERENCE ON CLUSTERING ASPECTS OF NUCLEAR STRUCTURE AND DYNAMICS (CLUSTER'12) 10TH INTERNATIONAL CONFERENCE ON CLUSTERING ASPECTS OF NUCLEAR STRUCTURE AND DYNAM 2013年

We investigate the three-body Coulomb breakup reactions of two-neutron halo nuclei and discuss the effect of binary subsystem correlations such as the of core-n and n-n. Furthermore, we calculate the invariant mass spectra. It is found that the final-state interactions of core-n and n-n binary subsystems dominantly determine the observed structures of the breakup cross sections, such as the low-lying enhancements. Y. Kikuchi, T. Myo, K. Kato, K. Ikeda

Multi-cluster problems: resonances, scattering and condensed states IOP PUBLISHING LTD 10TH INTERNATIONAL CONFERENCE ON CLUSTERING ASPECTS OF NUCLEAR STRUCTURE AND DYNAMICS (CLUSTER'12) 10TH INTERNATIONAL CONFERENCE ON CLUSTERING ASPECTS OF NUCLEAR STRUCTURE AND DYNAM 2013年

This talk is mainly concerned with many-body resonances in nuclear physics. We extensively discuss the structure and reactions of multi-cluster systems using the complex scaling method (CSM). We expound three interesting problems in recent studies of multi-cluster systems. First, we discuss four-and five-body resonances in A=7 (He-7, B-7) and A=8 (He-8, C-8) systems, respectively. The observed states are well explained and many additional states are predicted. Second, the Coulomb breakup reactions of two-neutron halo nuclei and the alpha-d scattering are investigated using a three-body model with CSM. Finally, we discuss the alpha-condensate-like states and their symplectic excitation properties in three-and four-alpha models for C-12 and O-16, respectively. K. Kato, T. Myo, Y. Kikuchi, T. Yoshida

複素座標スケーリング法を用いた散乱状態の記述と2中性子ハロー核のクーロン分解反応への適用 素粒子論研究 素粒子論研究 119巻 4B号 pp.E188-E197~ 0371-1838 2012年 02月 20日

菊地右馬, 明孝之, 高階正彰, 加藤幾芳, 池田清美

複素座標スケール変換した<sup>4</sup>He+N+NモデルによるA=6系の研究 原子核研究 原子核研究 55巻 Supplement 1号 pp.67~70 0367-4169 2011年 04月

栗原希美, 菊地右馬, 加藤幾芳

Complex-scaled cdcc method for nuclear breakup reactions Hadron and Nuclear Physics 2009, HNP 2009 Hadron and Nuclear Physics 2009, HNP 2009 pp.361~365 2010年 12月 01日

In this talk, we propose applying the complex-scaling method to CDCC, where the internal coordinate and momentum of projectile nucleus are complex- scaled. We show that the continuous S matrix element of breakup reaction is obtained without smoothing function. M. Takashina, M. Takashina, T. Myo, T. Myo, Y. Hirabayashi, Y. Kikuchi, K. Kato

<sup>5</sup>He,<sup>5</sup>Li不安定核の共鳴状態 原子核研究 原子核研究 54巻 Supplement 1号 pp.79~82 0367-4169 2010年 02月

立石謙太, 菊地右馬, 加藤幾芳

二体(<sup>4</sup>He+d),三体(<sup>4</sup>He+p+n)クラスター模型を用いた<sup>6</sup>Liの構造とE2遷移強度 原子核研究 原子核研究 54巻 Supplement 1号 pp.110~113 0367-4169 2010年 02月

和野惇, 菊地右馬, 平林義治, 明孝之, 加藤幾芳

Di-neutron correlations in <sup>6</sup>He through Coulomb breakup reactions CERN-Proceedings CERN-Proceedings 1巻 pp.99~105 2078-8835 2010年 01月 01日

The internal correlations of binary subsystems not only in the ground state but also in excited states of 6He are investigated through the Coulomb breakup reaction. For the excited states, to investigate the internal correlations, the two-dimensional energy distributions of the E1 strength are calculated with respect to the relative energy in the binary subsystems, and the importance of the final state interactions are discussed. For the ground state, the E1 strength distributions are calculated by using two types of wave functions with and without strong di-neutron correlations, and the contributions from the di-neutron correlations are investigated. Yuma Kikuchi, Takayuki Myo, Masaaki Takashina, Kiyoshi Kato, Kiyomi Ikeda

二体(<sup>4</sup>He+d),三体(<sup>4</sup>He+p+n)クラスター模型を用いた<sup>6</sup>Liの構造とd(α,γ)<sup>6</sup>Li反応 原子核研究 原子核研究 53巻 Supplement 1号 pp.96~99 0367-4169 2009年 03月

和野惇, 菊地右馬, 平林義治, 明孝之, 加藤幾芳

Di-neutron correlations and their dependence on coupling to continuum Institute of Physics Publishing Journal of Physics: Conference Series Journal of Physics: Conference Series 111巻 1号 1742-6596 2008年 05月 01日

We investigate the two-neutron correlations in 6He and 11Li nuclei through the density distributions of two valence neutrons. In this work, we use the two-neutron wave functions for halo nuclei within the extended three-cluster model assuming the core+n+n structures, where the internal correlations in the core nucleus is taken into account. For the 6He nucleus, the mixing of higher partial waves increases the spin singlet states slightly and enhances the di-neutron correlations. For the 11Li nucleus, a large s-wave mixing suppressed to form the spin triplet states and the di-neutron correlations are dramatically enhanced by the large amount of the singlet states. ? 2008 IOP Publishing Ltd. Y. Kikuchi, T. Myo, K. Kato, K. Ikeda

Role of the explicit tensor correlation in neutron halo nuclei Institute of Physics Publishing Journal of Physics: Conference Series Journal of Physics: Conference Series 111巻 1号 1742-6596 2008年 05月 01日

We propose a new mechanism to explain the disappearance of the N = 8 shell gap in 10,11Li with the tensor correlation. We first take into account the tensor correlation fully in the 9Li core in the so-called tensor-optimized shell model. In 10,11Li, the tensor correlations in 9Li are Pauli-blocked by additional two neutrons, which makes the p-state configurations pushed up in energy. As the final result including the pairing correlations, by solving the coupled 9Li+n+n problem, the N = 8 shell gap naturally disappears in 10,11Li, such as the s 2 component with around 50% in 11Li. ? 2008 IOP Publishing Ltd. T. Myo, Y. Kikuchi, K. Kato, H. Toki, K. Ikeda

Borromean系における3体クラスター構造と反応機構 原子核研究 原子核研究 52巻 Supplement 4号 pp.51~54 0367-4169 2008年 03月

菊地右馬, 明孝之, 高階正彰, 加藤幾芳, 池田清美

Description of three-body scattering for astrophysics AIP Conference Proceedings AIP Conference Proceedings 1016巻 pp.445~447 0094-243X 2008年 01月 01日

? 2008 American Institute of Physics. A new and simple discription of the three-body scattering states, which is based on the Lippmann-Schwinger equation and the complex scaling method, is developed. As applications of this method, the energy distribution of the E1 transition strength for 6He is calculated. It is also shown that the correlations of subsystems in 6He are well reproduced. Y. Kikuchi, T. Myo, M. Takashina, K. Kat?, K. Ikeda

<sup>6</sup>HeにおけるE1遷移と1<sup>-</sup>連続状態の効果 素粒子論研究 素粒子論研究 115巻 4号 pp.D88-D90~ 0371-1838 2007年 10月 20日

菊地右馬, 明孝之, 加藤幾芳, 池田清美

<sup>6</sup>He核のスキン構造と2中性子相関 原子核研究 原子核研究 51巻 Supplement 1号 pp.78~81 0367-4169 2007年 03月

菊地右馬, 明孝之, 加藤幾芳, 池田清美